System and method for transmitting/receiving three dimensional video based on digital broadcasting

ABSTRACT

Provided is a system and method for transmitting and receiving 3D video based on digital broadcasting. The system includes: an encoder for generating 2D ES and 3D supplementary ES by encoding 2D video and 3D supplementary data; a packetizer for generating 2D video PES and 3D supplementary PES by packetizing the 2D video ES and the 3D supplementary ES; a PSI generator for generating a PSI; a TS generator for generating 2D video TS and 3D supplementary TS for the 2D video PES and the 3D supplementary PES; a multiplexer for multiplexing the transport streams to transmit the 2D video TS as a normal stream and transmit the 3D supplementary TS, the PSI TS and 3D video synch data TS as robust stream; and a modulator for modulating the multiplexed TS according to a DTV specification and transmitting the modulated TS.

TECHNICAL FIELD

The present invention relates to a system and method fortransmitting/receiving three dimensional (3D) video based on digitalbroadcasting; and more particularly, to a system and method fortransmitting/receiving 3D video for enabling 3D digital broadcastingwhile sustaining the backward compatibility with a conventional twodimensional (2D) digital broadcasting system by transmitting a 2D imagestream as an normal stream and transmitting the supplementaryinformation for 3D broadcasting, for example, image data of other viewpoints, depth information, and disparity information, using a robuststream synchronized with the normal stream based on ATSC E-VSB schemeused in conventional digital broadcasting.

BACKGROUND ART

Conventional 3D video transceiving technologies for servicing threedimensional (3D) video contents based on a digital broadcastingtransmission system were introduced in a Korean Patent Publication No.1999-00600127, entitled “Method and apparatus for transmitting/receiving3D video in digital broadcasting,” and published on Jul. 26, 1999, aKorean Patent Publication No. 1995-0010662 entitled “Method forprocessing 3D video signal transmitting and receiving 3d broadcasting”,and published on Apr. 28, 1995, and a Korean Patent Publication No.1989-0015620 entitled “Television for receiving 3D video signal”, andpublished on Aug. 30, 1989.

According to these conventional 3D video transceiving technologies, atransmitter transmits a MPEG-TS with supplementary packet identifier(PID) information for identifying a left image data and a right imagedata of a stereoscopic 3D video additionally with typical PIDinformation that represents whether the MPEG-TS is audio/video data orsupplementary data. Then, a receiver extracts left image data and rightimage data from a 3D video data, and reproduces the 3D video using twodecoders. As described above, the conventional technologies splits theleft image data and the right image data by adding the supplementary PIDvalue into four program map tables (PMT) for identifying a left videosignal, a right video signal, an audio signal and supplementaryinformation.

As described above, the conventional 3D transceiving technologies use aplurality of independent program map tables for the left image and theright image in order to display a stereoscopic 3D video. The pluralityof program map tables increase the system complexity. Also, theconventional 3D transceiving technologies have the incompatibilityproblem with a typical digital broadcasting technology that uses one PMTper each channel. Since the conventional 3D transceiving technology hasa program specific information (PSI) and transport stream (TS) structurefor displaying only 3D video, it further have incompatibility problem toa typical broadcasting system that displays only 2D video.

Also, the information for generating 3D video includes image data of twoview points, image data of one view point with a disparity map, or imagedata of one view point with a depth map. However, the conventionaltechnology teaches only image data of two view points.

DISCLOSURE OF INVENTION Technical Problem

It is, therefore, an object of the present invention to a system andmethod for transmitting/receiving 3D video for enabling 3D digitalbroadcasting while sustaining the backward compatibility with aconventional two dimensional (2D) digital broadcasting system bytransmitting a 2D image stream as an normal stream and transmitting 3Dsupplementary data for 3D broadcasting, for example, image data of otherviewpoints, depth information, and disparity information, using a robuststream synchronized with the normal stream based on ATSC E-VSB schemeused in conventional digital broadcasting.

Technical Solution

In accordance with one aspect of the present invention, there isprovided a system for transmitting three dimensional (3D) video based ondigital broadcasting, including: an encoding unit for generating twodimensional (2D) video elementary stream (ES) and 3D supplementary dataES by independently encoding 2D video and 3D supplementary data; apacketizing unit for generating a 2D video packetized ES (PES) and a 3Dsupplementary PES by independently packetizing the 2D video ES and the3D supplementary ES generated at the encoding unit; a program specificinformation (PSI) generating unit for generating a PSI representing the3D supplementary data is transmitted as a robust stream; a transportstream (TS) generating unit for generating a 2D video TS and a 3Dsupplementary TS for the 2D video PES and the 3D supplementary PES fromthe packetizing unit and a PSI TS for the PSI generated from the PSIgenerating unit; a multiplexing unit for multiplexing the transportstreams from the TS generating unit to transmit the 2D video TS as anormal stream and to transmit the 3D supplementary TS, the PSI TS and a3D video synch data TS as a robust stream; and a modulating unit formodulating the multiplexed TS according to a specification of a digitaltelevision (DTV) and transmitting the modulated TS.

In accordance with another aspect of the present invention, there isprovided a system for receiving three dimensional (3D) video based ondigital broadcasting including: a demodulating unit for receiving adigital broadcasting signal and splitting the received digitalbroadcasting signal into a normal stream and a robust stream; ademultiplexing unit for extracting a program specific identification(PSI) data and a 3D video synch data from the robust stream, extractinga 2D video TS and a 3D supplementary TS from the normal stream and therobust stream using the extracted PSI data, and outputting the extracted2D video TS and 3D supplementary TS in forms of a 2D video ES and a 3Dsupplementary ES; a decoding unit for decoding the 2D video ES and the3D supplementary ES from the de-multiplexing unit; a 3D video mixingunit for bypassing the decoded 2D video from the decoding unit accordingto a display type requested by a user, or producing a 3D video by mixingthe decoded 2D video and 3D supplementary data from the decoding unit;and a controlling unit for controlling the 3D video mixing unit togenerate the 3D video using the 3D video synch data extracted from thede-multiplexing unit.

In accordance with further another aspect of the present invention,there is provided a method for transmitting 3D video based on digitalbroadcasting, including the steps of: a) generating 2D video packetizedelementary stream (PES) and 3D supplementary data packetized elementarystream (PES) by independently encoding and packetizing 2D video and 3Dsupplementary data; b) generating a program specific identification(PSI) representing the 3D supplementary data is transmitted as a robuststream; c) generating a 2D video TS and a 3D supplementary TS for the 2Dvideo PES and the 3D supplementary PES from the step a) and a PSI TS forthe PSI generated from the step b); d) multiplexing the transportstreams from the step c) to transmit the 2D video TS as a normal streamand to transmit the 3D supplementary TS, the PSI TS and a 3D video synchdata TS as a robust stream; and e) modulating the multiplexed TSaccording to a specification of a digital television (DTV) andtransmitting the modulated TS.

In accordance with further still another aspect of the presentinvention, there is provided a method for receiving 3D video based ondigital broadcasting including the steps of: a) receiving a digitalbroadcasting signal and splitting the received digital broadcastingsignal into a normal stream and a robust stream; b) extracting a programspecific identification (PSI) data and a 3D video synch data from therobust stream, extracting a 2D video transport stream (TS) and a 3Dsupplementary TS from the normal stream and the robust stream using theextracted PSI data, and outputting the extracted 2D video TS and 3Dsupplementary TS in forms of a 2D video ES and a 3D supplementary ES; c)decoding the 2D video ES and the 3D supplementary ES from the step b);and d) bypassing the decoded 2D video from the step c) according to adisplay type requested by a user, or generating a 3D video by mixing thedecoded 2D video and 3D supplementary data from the step c).

Advantageous Effects

A system and method for transmitting/receiving 3D video according to thepresent invention can minimize difficulties to embody a 3D videobroadcasting system and provide the backward compatibility with thetypical 2D digital broadcasting system by transmitting 3D supplementarydata using additional robust stream based on ATSC E-VSB scheme used inconventional digital broadcasting.

Thus, the system and method for transmitting/receiving 3D videoaccording to the present invention allows a user having a conventionaldigital broadcasting receiver to enjoy 2D video broadcasting and alsoallows a user having a 3D video digital broadcasting receiver toselectively enjoy one of 2D video or 3D video broadcasting.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating a system for transmitting 3Dvideo based on digital broadcasting in accordance with an embodiment ofthe present invention; and

FIG. 2 is a block diagram illustrating a system for receiving 3D videobased on digital broadcasting in accordance with an embodiment of thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Other objects and aspects of the invention will become apparent from thefollowing description of the embodiments with reference to theaccompanying drawings, which is set forth hereinafter.

FIG. 1 is a block diagram illustrating a system for transmittingthree-dimensional (3D) video based on digital broadcasting in accordancewith an embodiment of the present invention. Hereinafter, a method fortransmitting 3D video according to an embodiment of the presentinvention will be described with the system for transmitting/receiving3D video.

As shown in FIG. 1, the 3D video transceiving system according to thepresent embodiment includes a 3D AV obtaining unit 10, an encoder 11, apacketizer 12, a program specific information (PSI) generator 13, atransport stream (TS) generator 14, a normal/burst stream multiplexer(Normal/Robust stream MUX) 15, and an E-xVSB modulator 16.

The 3D AV obtaining unit 10 obtains 2D A/V data and 3D supplementarydata from 3D contents. Herein, the 2D A/V data is left and rightaudio/video data for 2D broadcasting and the 3D supplementary datadenotes supplementary information for 3D broadcasting. That is, the 3Dsupplementary data is information for reproducing three-dimensionalimages and includes images of other view points different from that ofthe 2D image, a disparity map, a disparity map with residual data, and adisparity map with residual texture. Herein, the 2D image denotes imagesfor two dimensional broadcasting. The images of other view points may bea right image if the 2D image is a left image, or it may be a left imageif the 2D image is a right image.

The encoder 11 includes a plurality of encoding units 111 and 112. Theencoder 11 independently encodes the AV data and the 3D supplementarydata, which are outputted from the 3D AV obtaining unit 10, andgenerates elementary streams (ES) for each data. That is, the audio dataand the 2D video data including one of the left and the right image areencoded by a corresponding one of the encoding units 111 and 112independently. Also, the 3D supplementary data is encoded by the otherindependently. After encoding, the decoders 111 and 112 output theelementary streams. MPEG-2 encoding units may be used as the encodingunits 111 and 112, or any widely known encoder having good compressionefficiency may be used, for example, MPEG-4 AVC.

The packetizer 12 includes a plurality of packetizing units 121 and 122.The packetizing units 121 and 122 packetize the 2D AV elementary streamand the 3D supplementary elementary stream outputted from the encoder11, thereby generating a packetized elementary stream (PES).

The program specific information (PSI) generator 13 generates PSI datathat represents that the 3D supplementary data is transmitted as arobust stream. That is, the PSI generator 13 defines a PID value and aPMT for the 3D supplementary ES in order to transmit the 3Dsupplementary ES as the robust stream.

The transport stream (TS) generator 14 includes a plurality of TSgenerating units 141 to 143. The TS generating units 141 to 143 generatetransport streams (TS) for the PES outputted from the packetizing units121 and 122 and the PSI data outputted from the PSI generator 13. Thatis, the TS generator 14 outputs a 2D AV TS, a 3D supplementary TS and aPSI TS. Herein, the 2D AV TS is an audio transport stream and a 2D videotransport stream.

The Normal/Robust stream MUX 15 multiplexes the 2D AV TS, the 3Dsupplementary TS and the PSI TS in order to transmit the 2DAV TS througha normal stream, and transmit the 3D supplementary TS, the PSI TS andsynch information for mixing a 3D video through a robust stream. Herein,the receiver will use the multiplexed 3D supplementary data and synchinformation for recovering a 3D video.

The E-xVSB modulator 16 modulates the multiplexed TS from theNormal/Robust stream MUX 15 according to a digital television (DTV)standard and transmits the modulated TS.

FIG. 2 is a block diagram illustrating a system for receiving 3D videobased on digital broadcasting in accordance with an embodiment of thepresent invention. Hereinafter, a method for receiving 3D videoaccording to an embodiment of the present invention will be describedwith the system for receiving 3D video.

Referring to FIG. 2, the 3D video receiving system according to thepresent embodiment includes an E-xVSB demodulator 21, a demultiplexer(DeMux) 22, a controller (control logic part) 23, a decoder 24, a 3Dvideo mixer 25, a 2D/3D video display 26, and a speaker 27.

The E-xVSB demodulator 21 receives a digital broadcasting signal throughan antenna. Herein, the digital broadcasting signal is transmitted basedon a dual mode ATSC E-VSB scheme. After receiving, the E-xVSBdemodulator 21 demodulates the received signal and obtains TSs. Then,the E-xVSB demodulator 21 splits the obtained TS into a normal streamand a robust stream.

The demultiplexer (DeMux) 22 receives the robust stream from the E-xVSBdemodulator 21, extracts the PIS data and the synch information formixing the 3D video from the robust stream, and splits the normal streamand the robust stream into the 2D video TS and the 3D supplementary TSusing the extracted PSI data. The demultiplexer 22 generates PES byanalyzing the split TS, and de-packetizes the generated PES, therebyoutputting the split TS as an elementary stream.

The decoder 24 includes an MPEG-2 decoder 241, a 3D supplementarydecoder 242, and an audio decoder 243. They decode the 2D ES, the 3Dsupplementary ES and the audio ES from the demultiplexer 22. Herein, theMPEG-2 decoder 241 decodes the 2D video ES outputted from the DeMux 22according to the MPEG-2 specifications and outputs the decoded 2D videoES to the 3D mixer 25. The 3D supplementary decoder 242 decodes the 3Dsupplementary ES inputted from the DeMux 22 and outputs the decoded 3Dsupplementary ES to the 3D mixer 25. Also, the audio decoder 243 decodesthe audio ES inputted from the DeMux 22 and outputs through the speaker27.

The 3D mixer 25 bypasses 2D video inputted from the decoder 241 orgenerates a 3D video by mixing the 2D video and the 3D supplementarydata inputted from the decoders 241 and 242. Then, the 3D mixer 25outputs the generated 3D video to the 2D/3D video display 26.

That is, the 3D mixer 25 checks a display type inputted from a user. Ifthe display type requested by the user is 2D image display, the 3D mixer25 ignores the 3D supplementary data and bypasses the original videothat is the 2D video transmitted as the normal stream to the 2D/3D videodisplay 26. If the display type requested by the user is 3D imagedisplay, the 3D mixer 25 generates the 3D video by mixing the 2D videoand the 3D supplementary data, and outputs the generated 3D video to the2D/3D display 26. In the 3D video generating step, the 3D supplementarydata formed of odd field images and even field images of the videosignal is mixed in a line-by-line manner, thereby outputting SD level 3Dvideo, where the SD level denotes a resolution of 720×480. Herein,garbage data in the 3D supplementary data is ignored. Also, theresolution of the 3D video may change depending on the display such as amonitor. Therefore, a video signal magnification/demagnification modulemay be added in a real display.

It is very important to accurately synchronize 2D video which is anoriginal video, for example, a left image, and 3D supplementary data,for example, a right image, in a frame unit in order to reduceeyestrain.

The controller 23 controls the de-multiplexing operation of the DeMux22, and controls the 3D video generating operation of the 3D mixer 25using the synch data extracted at the DeMux 22. The controller 23synchronizes the 2D video or the 3D video, which are outputted from the3D mixer 25 to the 2D/3D video display 26 with the audio outputted fromthe audio decoder 243.

The 2D/3D video display 26 receives the 2D video or the 3D videotransferred from the 3D video mixer 25, and the speaker 27 reproducesthe audio data outputted from the audio decoder 243.

The above described method according to the present invention can beembodied as a program and stored on a computer readable recordingmedium. The computer readable recording medium is any data storagedevice that can store data which can be thereafter read by the computersystem. The computer readable recording medium includes a read-onlymemory (ROM), a random-access memory (RAM), a CD-ROM, a floppy disk, ahard disk and an optical magnetic disk.

The present application contains subject matter related to Korean patentapplication Nos. 2005-120700 and 2006-69959 filed with the KoreanIntellectual Property Office on Dec. 9, 2005, and Jul. 25, 2006, theentire contents of which is incorporated herein by reference.

While the present invention has been described with respect to certainpreferred embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the scope of the invention as defined in the following claims.

We claim:
 1. A system for transmitting three dimensional (3D) videobased on digital broadcasting, comprising: an encoder generating twodimensional (2D) video elementary stream (ES) and 3D supplementary dataelementary stream (ES) by independently encoding 2D video and 3Dsupplementary data, wherein the 2D video data includes images of a 2Dviewpoint, and each image of the 3D supplementary data is from aviewpoint that is different than the 2D viewpoint; a packetizergenerating a 2D video packetized ES (PES) and a 3D supplementary PES byindependently packetizing the 2D video ES and the 3D supplementary ESgenerated at the encoder; a program specific information (PSI) generatorgenerating a PSI representing the 3D supplementary data; a transportstream (TS) generator generating a 2D video TS and a 3D supplementary TSfor the 2D video PES and the 3D supplementary PES from the packetizerand a PSI TS for the PSI generated from the PSI generator; a multiplexermultiplexing the transport streams from the TS generator to transmit the2D video TS as a normal stream and to transmit the 3D supplementary TS,the PSI TS and a 3D video synch data TS as a robust stream; and amodulator configured to modulate the multiplexed TS according to aspecification of a digital television (DTV) and transmitting themodulated TS.
 2. The system as recited in claim 1, further comprising a3D broadcasting data receiver obtaining 2D video data and 3Dsupplementary data from 3D video contents.
 3. The system as recited inclaim 1, wherein the 3D supplementary data includes a video of adifferent view point from the 2D video, a disparity map, a depth map, adisparity map with residual data, and a disparity map with residualtexture.
 4. A method for transmitting three dimensional (3D) video basedon digital broadcasting, comprising the steps of: a) generating twodimensional (2D) video packetized elementary stream (PES) and 3Dsupplementary data PES by independently encoding and packetizinq 2Dvideo and 3D supplementary data, wherein the 2D video data includesimages of a 2D viewpoint, and each image of the 3D supplementary data isfrom a viewpoint that is different than the 2D viewpoint; b) generatinga program specific identification (PSI) representing the 3Dsupplementary data; c) generating a 2D video TS and a 3D supplementaryTS for the 2D video PES and the 3D supplementary PES from the step a)and a PSI TS for the PSI generated from the step b); d) multiplexing thetransport streams from the step c) to transmit the 2D video TS as anormal stream and to transmit the 3D supplementary TS, the PSI TS and a3D video synch data TS as a robust stream; and e) modulating themultiplexed TS according to a specification of a digital television(DTV) and transmitting the modulated TS.
 5. The method as recited inclaim 4, wherein the 3D supplementary data includes a video of adifferent view point from the 2D video, a disparity map, a depth map, adisparity map with residual data, and a disparity map with residualtexture.
 6. The method as recited in claim 4, wherein the step a)includes the steps of: a-1) generating a 2D video elementary stream (ES)and a 3D supplementary ES by independently encoding the 2D video and the3D supplementary data; and a-2) generating a 2D video packetized ES(PES) and a 3D supplementary PES by independently packetizing the 2Dvideo ES and the 3D supplementary ES from the step a-1).